CLASSIFICATION OF ENZYMES

Enzymes are considered biological catalysts and always a protein. Enzymes speed up the rate of chemical reactions in a cell. Enzymes also build various substances while breaking others as well. Thus, Enzymes cannot be destroyed and used over and over again. In specific, a cell contains thousands of various types of enzyme molecules, whereas each molecule has a specific reaction. 

Overview of enzymes

Enzymes, basically protein-based catalysts, are involved in numerous chemical reactions. These are blood coagulation, growth, healing, breathing, reproduction, digestion and other biological activities. Additionally, various types of enzymes help to create a cellular response by signal transduction, as these are known as protein kinases which catalyse protein phosphorylation. In the catabolism process, enzymes help to break large proteins, sugar and fat into smaller pieces, while in the anabolism process, the small particles are used in building blocks by refreshing the body through tissue repair, regeneration etc. Enzymes also transfer energy into chemical forms by storing it in ATP. In regards, enzymes create pathways to bodily substances which need to transfer into the cellular constituents through oxidation, hydrolysis, reduction etc. In addition, enzymes also play important roles in immune response, the aging process, movement generation with myosin hydrolysing ATP for creating muscle contraction and transporting substances as a part of the cytoskeleton and many more.

Definition of enzymes

Enzymes consist of either proteins or ribozymes (RNA), a molecule that acts as the catalyst for speeding up the chemical reaction. Enzymes can be synthesised biologically or through processes like synthetically. Enzymes have sequence characteristics of amino acid, which creates a 3D structure to give molecules unique properties. Enzymes are proteins composed of amino acids, which are joined together with peptide bonds, encoded by DNA in cells. On the other hand, enzymes that are not protein in nature, are generally exemplified by the ribozymes. 

Classification of enzymes 

Enzymes are classified as per their reactive nature. The International Union of Biochemistry and Molecular Biology have established the classification of enzymes by measuring every enzyme’s nomenclature by an EC number. The classification of enzymes has been stated below. 

• EC 1 Oxidoreductases: Oxidoreductases generally consist of a large class of enzymes, which catalyse the electronic transfer from reductant (an electron donor) to oxidant (an electron acceptor) molecule. Oxidoreductase also fulfills an essential role in both anaerobic mechanisms and aerobic metabolism.

Function: A substance of oxidoreductases, as coenzyme accepts, electrons and hydrogens, are transferred into oxygens, in the metabolic system. 

• EC 2 Transferases: Transferases enzymes catalyze transfer amongst a group of atoms. These atoms are amine, carbonyl, carboxyl, acyl, methyl, phosphoryl and glycol form a donor substrate to the acceptor compound. 

Function: Transferases have more than 450 enzymes that catalyze the transfer of various functional groups. Additionally, Transferases catalyse the ‘transfer’ of H2.

• EC 3 Hydrolases:  Hydrolase’s enzymes catalyze the hydrolysis among the proteins, starch,fats, nucleic acid, phosphate satire and various macromolecular substances. 

Function: Hydrolases break chemical bonds to produce smaller molecules from large ones. Various hydrolases are lipases, glycosidases, phosphatases, nucleosidases and peptidases. 

• EC 4 Lyases: Lyases enzymes, catalyse the process of addition and removal of several elements of water (hydrogen and oxygen), CO2 (carbon and oxygen) or Ammonia (nitrogen and hydrogen) into double bonds. 

Function: Decarboxylases, a substance of lyases, helps to remove CO2,from the amino acid, while dehydrases remove water.

• EC 5 Isomerases: Isomerases catalyse the isomerization changes within one singular molecule. Isomerases also involve a catalyzed reaction in a molecules’ structural rearrangement. For instance, isomerases catalyze “L-alanine’s conversion” into an isomeric form that is “D-alanine”.

Function:  Isomerases have several biological relevance. Isomerases are also present in the genome and metabolism in most living beings, which catalyses up to 4% of the overall biological reaction that is present in central metabolism. 

• EC 6 Ligases: Ligases play important roles in maintaining genomic integrity by joining the breaks in DNA’s phosphodiester backbone.

Function: These steps occur during recombination and replication of DNA as a result of DNA’s damage and its repair.

Mechanism of enzymes activity 

Initially, enzymes attract substrates in their active state, acting as catalysts in chemical reactions for which the products are formed. Thereafter, it allows the products to get separate from the surface area. One enzyme and its substrates’ ‘ together form an “enzyme-substrate complex”.

[E + S ⇔ ES ⇔ EP⇔ E+P]

It is the most simplified equation followed in enzyme mechanism and more appropriately described through the Lock and Key model. 

Conclusion 

To conclude this topic ‘ an overview of enzymes’ has been established by discussing their activities in the bodies of living beings. The chemical processes are known as metabolism which helps us to maintain our BMI rate. In this regard, various classification of enzymes has been made, while mentioning its mechanism too.